Pole-changer.



No. 647,29l. Patented Apr. I0, 1900. W. M. CHAPMAN.

POLE CHANGER.

(Application filed Aug. 10, 1899.)

(No Model.)

f/VVENTUR] WITNESE'EE THE norms Pz'rsnr c0. PNOTD-LIYHQ. WASNINGTDN, n.c.

NiTED STATES PATENT CFFIcE.

VINTHROP M. CHAPMAN, OF NEEDHAM, MASSACHUSETTS, ASSIGNOR OF ONE-HALF TOCHARLES V. RICHARDS, OF SAME PLACE.

POLE-CHANGER.

SPECIFICATION forming part of Letters Patent No. 647,291, dated April10, 1900.

Application filed August 10, 1899. Serial No. 726,785. (No model.)

To all whom it mag concern.-

Be itknown that LWINTHROP M. CHAPMAN, of Needham, county of. Norfolk,and State of Massachusetts, have invented a'n Improvement inPole-Changers, of which the following description, in connection withthe accompanying drawings, is a specification, like letters and figureson the drawings representing like parts.

The present invention relates to a polechanging device fordynamo-electric machines, said device being adapted to be used in caseswhere it is necessary to obtain a current always flowing in the samedirection from a dynamo-electric machine which may be driven in eitherdirection. a

The device is especially adapted for those car-lighting systems in whicha dynamo is driven by the rotation of the car-axle, so that the armatureis liable to be rotated in one direction as often as in the other. It isto be understood, however, that the invention is not limited to suchspecific use, since polechanging devices embodying the invention may beused for various purposes.

The device embodying the invention comprises a'switch member adapted tobe shifted from one set of contacts to another, so that no matter whichway the armature of the dynamo is traveling the positive brush will beconnected with the positive line-terminal and the negative brush withthe negative lineterminal, so that the polarity of the dynamobrushes maybe shifted without varying the direction of current in the line-circuit.To shift the said switch member from one position to the other inresponse to a change in direction of rotation of the dynamo-armature,the said armature is arranged to cooperate with an actuating devicewhich will travel in one direction or the other, according to thedirection of travel of the armature, and the said actuating device isprovided with engaging portions, one of which will engage the switchmember when the actuator is traveling in one direction and the other ofwhich will engage the switch member when the actuator is traveling inthe opposite direction. The actuator and switch member are so arrangedwith relation to each other that as soon as the actuator has pushed thesaid switch member a sufficient distance to bridge the proper contactsit will become disengaged therefrom and will not produce any furtheroperation. The switch member is then left in a position to be operatedupon by the other engaging portion of the actuator if the direction oftravel of the dynamo-armature is changed.

It may not in some cases be essential to employ more than one engagingportion for each member, since such a pole-changer might be utilized incases where the automatic changing of the poles need be accomplishedonly when the direction of rotation of the armature has been oncechanged. When the device is used for the purpose above named,however-that is to say, in car-lighting systemsit is desirable that itshould be completely automatic, the parts therefore being duplicated, sothat the device will operate in response to every change in thedirection of rotation of the armature.

Figure 1 is a side elevation of a sufficient portion of a deviceembodying the invention to illustrate the construction and operationthereof. Fig. 2 is a similar view illustrating a modification, and Fig.3 is a sectional detail showing a portion of one of the switch-arms andits bridging-contact.

As herein shown, the brushes a and b of may be positive or negative,according to the the armature A, either of which brushes direction ofrotation of said armature, are

connected, respectively, with the contact: pieces 2 and 4 of a line ofcontact-pieces 1, 2, 3, 4:, and 5, which are adapted to be bridged bythe switch member 0, which is shown as having bridging projections c and0 each of which projections is provided with a contact-piece, Fig. 8,adapted to bridge two of the said contacts and separated from the switchmember by a suitable insulating material.

The negative line-terminal is shown as connected with the contact 3, andthe positive line-terminal is shown as connected with the contacts 1 and5, the switch being shown in such a position that the positiveline-terminal is connected with the brush a and thenegativeline-terminal with the brush b. The circuit in this case is from brush ato contact 2, across the switch member 0 to contact 1, and thence to thepositive terminal of the line, around the line-circuit, (not shown,) andback through the negative terminal to contact 3, across switch member 0to contact 4-, and thence to the brush Z). It, therefore, the directionof rotation of the armature is changed so that the brush 1) becomes thepositive brush and the brush at the negative brush, it is necessary toshift the switch member 0 to the right, the circuit then being frombrush Z) to contacts et and 5, which are then connected by the switchmember 0 and thence to the positive terminal of the line,aroun d theline-circuit, and back through the negative terminal to cont-act 3,thence through the switch member 0 which then bridges the contacts 3 and2, to said cont-act 2, and from said contact 2 to brush a. In order toeifect these changes, it is necessary that the switch member 0 should beshifted from one position to the other each time the direction ofrotation of the armature is changed and then left stationary so long asthe armature continues traveling in the same direction. To this end theswitch member is arranged to cooperate with a traveling actuator (Z,herein shown as an arm carried by a worm-gear (Z cooperating with a wormA on the shaft of the armature A, it being obvious, therefore, that thedirection of rotation of said gear will be changed when that of thearmature is changed. The said actuator (Z is arranged, when the switchmember is in the position shown and the worm-gear is traveling in thedirection of the arrow, to engage and move the switch member 0, which isshown as provided with a pawl 0', adapted to be positively engaged asthe actuator travels with the arrow. As'shown in Fig. 1, the switchmember 0 is pivotally supported at c on an axis eccentric to the axis ofthe actuator d, it being obvious, therefore, that the actuator (Z andpawl 0 will remain in engagement only until the point of the said pawlhas reached the position at which its path of travel crosses the path oftravel of the said actuator, the said paths of travel being indicated indotted lines.

The parts are so arranged that during the time the actuator is inengagement with the pawl c the switch member cwillbe moved far enough toshift the contacts and change the circuits, as above described. It isfurther obvious that as soon as the switchmember c has been thus shiftedthe pawl c will remain out of the path of the actuator cZ, so that nofurther movement will take place while the actuator (Z is travelinginthe direction of the arrow.

In order that the shifting may take place automatically in eitherdirection, the actuator is shown as provided with a second projection (Zadapted to cooperate with a pawl c symmetrically arranged with the pawlc and arranged. to travel along the same curved path. i lssnming,therefore, that the actuator (Z is traveling in the opposite directionfrom that indicated by the arrow and that the switch member is in theother position from that shown, it will be seen that the pawl 0 will beengaged by the projection d, as has already been described with relationto the projection (Z, and will carry the switch member 0 to the positionshown.

The pawls described are duplicates of each other, both operating inexactly the same way in order to render the device completelyauto matic,it being obvious that one of said pawls might be omitted withoutdepartingfrom the invention-as, for example, if it were desired to causethe pole-changer to operate automatically in one direction only. \Vhentwo pawls are employed, as shown, the only object in duplicating theengaging portion of the actuator is to afford means for causing thememher which engages a pawl at each rotation to slide past with theleast possible friction, the two projections being offset and eachprovided with an inclined surface at one side and an abrupt shoulder atthe other. As shown in the drawings, for example, the member (Zcooperates with the pawl c only, being out of alinement with the pawl 0and if the actuator is traveling in the direction opposite to thatindicated by the arrow the inclined surface of the member (Z will engagethe pawl c, so as to lift said pawl with the least possible friction.With the pawls in alinement it is ob vious that one engaging project-ionwould do the work, but neither surface could be inclined or beveled andmore friction would be encountered in lifting the pawl.

It is desirable that the pawl which has been positively engaged shouldbe moved after such engagement completely out of the path of theactuator, so as to be wholly out of contact therewith during the furtherrotation of the actuator in the same direction. To this end each pawl isprovided with a spring 0, the tendency of which is to move the said pawlsomewhat out of its normal path, (indicated by the dotted line,) the endof the pawl being so shaped with relation to the engaging shoulder ofthe actuator that the said shoulder when in positive engagement with thepawl will wedge the same down close against its spring 0, which springwhen its pawl is released by the actuator will raise said pawl out ofthe path of travel of the actuator. Thus after the pole-changer is onceshifted the only engagement between it and the actuator is between theunder inclined surface of one of the pawls and the actuating arm orarms, so that the pawl easily yields without any material wear. The saidpawls are held in their normal position by means of a spring 0 havingatension somewhat slighter than that of the springs a, so as to keep thepawls in their normal position without interfering with the function ofthe springs a.

It is obviously not essential that the actuating members and the pawlsshould travel in different paths, since other means may be devised fordisengaging the parts after the switch member has been moved asufficient distance. As shown in Fig. 2, for example, the switch member0 and the actuator 01 are mounted on a common axis and the pawls c and 0are arranged to cooperate with disengaging members c having inclinedsurfaces arranged to engage-pins or projections 0 upon the pawls, thesaid inclined surfaces being stationary with relation to the actuatingdevice. Assuming, therefore, that the direction of the armature has justbeen changed and that the actuator (Z Fig. 2, is traveling in thedirection of the arrow, it will be seen that the said actuator willengage the pawl c and shift the member 0 until the projection c ridesalong the inclined surface 0 thus lifting the said pawl out ofengagement with the shoulder. To carry the said pawl entirely out ofengagement with said shoulder, as above described, the inclined surface0 is formed upon a spring the tension of which is such that the springwill yield slightly before forcing the pawl out of engagement with theshoulder, the said pawl moving after it is actually disengaged to theposition of the pawl 0 The downward movement of the pawls in thisinstance is limited by stops 0 when the said pawls are not controlled bythe inclined surfaces 0 It will be seen from the foregoing descriptionthat if the direction of movement of the armature is changed the poleswill be correspondingly changed at the end of a very small interval oftime.

The device is simple and positive in its operation and is thereforeespecially adapted for car-lighting systems, where the direction ofrotation of the armature maybe frequently changed or may remainunchanged for a considerable period of time.

It is not intended to limit the invention to the specific constructionshown and described, since modifications may be made without departingfrom the invention.

I claim" 1. A pole-changer comprising a traveling switch member tocooperate with suitable contacts; a traveling actuator cooperating withthe armature of the dynamo to be controlled and arranged to change itsdirection of travel when the direction of travel of the said armature ischanged; an engaging member traveling with said actuator and arranged toengage and move the said switch member; and means for disengaging saidactuator from said switch member after the latter has been moved apredetermined distance, as set forth.

2. The combination with a pole-changing.

switch; of a rotating actuator cooperating therewith; a pawl carried bysaid switch and lying in the path of said actuator and adapted to bepositively engaged thereby during its movement in one direction but toyield before the same during its movement in the other direction; andmeans for disengaging the said pawl from said actuator after it has beenmoved thereby a predetermined distance, as set forth.

The combination with a pivotally-supported pole-changing switch; of apair of pawls carried by said switch, the said pawls pointing inopposite directions; a rotating actuator adapted to positively engageone of said pawls when the actuator is traveling in one direction andthe other pawl when the actuator is traveling in the opposite direction;and means for disengaging the pawl from the actuator when the switchmember has been moved a predetermined distance, as set forth.

4. The combination with a pivotall'y-supported pole-changing switch; ofa pair of pawls carried by said switch; the said pawls pointing inopposite directions; a rotating actuator provided with engaging surfacesto cooperate respectively with said pawls, one of said surfaces beingadapted to positively engage one of said pawls when the actuator istraveling in one direction and the other surface being adapted topositively engage the other pawl when the actuator is traveling in theopposite direction; and means for disengaging the pawl from the actuatorwhen the switch member has been moved a predetermined distance, as setforth.

5. The herein-described means for chang* ing the brush connections of adynamo-electric machine from one line-terminal to the other in responseto a change in the direction of travel of the armature, which comprisean actuator adapted to travel continuously in one direction or the otheraccording to the direction of travel of' the armature, and a switchmember having connected therewith a latching projection or pawl wherebysaid member will be moved by said actuator in one direction but not inthe other.

6. The herein-described means for changing the brush connections of adynamo-elec-. tric machine from one line-terminal to the other inresponse to a change in the direction of travel of the armature, whichcomprise a continuously-traveling actuator adapted to change itsdirection in response to a change in the direction of rotation of thearmature, and a switch member having a latching projection to cooperatewith said actuator to move the switch member when the direction ofmovement of said actuator has been changed.

7. The combination with'the actuator, of the switch member, the engagingportion of the switch member whereby said member is moved by theactuator, said engaging portions being adapted to move out of engagementwith each other at the end of a predetermined movement of the switchmember, and means for producing a further movement of one of said partswhereby an open space is left between them during the subsequent Intestimony whereof I have signed my movement of the actuator. name tothis specification in the presence of 8. The combination with theactuator (Z; of two subscribing Witnesses. the switch member 0; the pawl0 connected VVINTHROP M. CHAPMAN. 5 with said switch member; and thespring 0 Witnesses:

or its equivalent, substantially as and for the HENRY J. LIVERMORE,

purpose described. JAS. .T. MALONEY.

